As reported in the Wall Street Journal, the federal government, via the Drug Enforcement Agency (DEA) tracks the location of millions of vehicle. They’ve engaged in this for nearly eight years, all without a warrant, or even public notice of the policy.

State and local law enforcement agencies operate most of these tracking systems, known as Automated License Plate Readers (ALPRs). These are mostly paid for by federal grant money. The DEA then taps into the local database to track the whereabouts of millions of people – for the simple act of driving – without having to operate a huge network itself.

Since a majority of federal license plate tracking data comes from state and local law enforcement, states can severely cripple this federal program. This page tracks state legislation in two forms: a) an express prohibition on most use without a probable cause warrant, and b) a prohibition on long-term retention of data and of transfers or use of that data by outside parties.

Blue – Introduced. Yellow – Passed one or more Houses. Green – Passed both Houses. Purple – Law, Step 1. Red – Law, Step 2.